Cyclone dust collector



PatentedA sept. 24, 1946 f,

oYcLoNEDUsT COLLECTOR f .Joe Crites, Evanston, Ill., assignerto'Colnbus'- tion Engineering Company, Inc., New-York, N. Y., acorporation of Delaware Application January 26, 1944,*seria1No. l519,763

This invention relates to certain new and useful improvements in cyclonedust collectors and has for itslprin'cipal object Ythe provision ofimproved constructions whereby a large percentage of .the dusty mayberemoved vfrom dust laden air in-al cyclone separator.

A cyclone separator of ordinary construction includes rarcylindricalupper portion and a lower conicalportion which terminates in adischargespout. j The dust laden air is introduced into the cylindricalupperportion of the separator at a v hold a fixed position. y*On thecontrary, itwhips tangent tov the inner surface thereof. The whirling ofthe air forms within the -casing two concentric spirals. The outerspiral` has a'higher pressure and moves downwardly toward the apex ofthe separator. It functions to Vprecipitate the dust'from the air. Theinner spiral has a lower pressure and moves vupwardly within the casing.Its function is to discharge theair from the sepavrator l after. thedust has" been removed.

The dust particles carried in the air, `o l" the outer spiral lare.thrown .outwardly toward the side ofY the casing, while the air,cleared ofthe dust, moves tangentially inward toward the vertical axisof the separator to form the inner low pressure spiral which, aspreviously mentioned, moves upwardly and discharges the air through acentral opening in the upper4 portion of the casing. j

The dust particles carried in the air of the outerspiral and thrownoutwardly toward the wall ofthe separator casing create a dust stratawhich has its maximum density adjacent the wall of the separator. Thisdense strata maybe relatively thin inithe upper portion of thefcasingbecause of its greater diameter, but the thicknessv of the V'strataincreases as it moves downwardly with the outer spiral into therestricted lower portion of the cone-shaped collector. Y,Cnlor'isequently, at the lower portion of the collector, the inner or less denseportion of the dust strata is brought into vcloser relation to the,boundary of the inner'low pressure spiral, whereby variations inA .airpressure, or otherrvariable influences may cause portions of thissuspended dust to be ydrawn into the said inner spiral and` therebycarried out of thev separator with the discharged air. However, the dustlost4 from a cycloneV separator is not necessarily confined to dust heldin suspension inthe above manner. On thecontrary, much of thedust lostfrom a cyclone separator Vmay have been previously Vprecipitatedrfromthe air and then subsequently picked up by a stemylike suction columnformed at the lower end of the inner spiral. This stem-like column doesnot or thrashes about within the restricted lower end of the casing andpicks :up the precipitated dust from the outer spiral near the wall ofthe collector. This dust is, therefore, held in the low pressure spiraland carried out of the separator casing with thev discharged air.

One of the principal objects of the present invention isto provide a newand simplied construction forrecapturing thedust picked up by the lowpressure inner spiral of vair which is within the outer or dustprecipitating spiral of a cyclone separator. y f i A further objectis toaccomplish the. above specifiedl objectsfby means of ya by-pass whichinterceptsjthejdust picked vup by the said'low pressure. inner spiraland redelivers it to the inletv end of the separator so that it will b'eI'eprecipitated in the separator and thereby make it practicable toremove substantiallyrall dust from the Vair in a sin'gle 'separator. o A

f by the feathered arrows.

A preferred embodimentv of the/invention is il-I lustrated in theaccompanying drawing, wherein: Eig.ll i' s ayertical'section takenthrough the cyclone separator constructed in accordance with thisinvention; and 'y i Fig. 2 is a fragmentary sectional view taken on line2,-2 of Fig. 11. I

The separator herein shown is of the cyclone type and includes a'cylindrical upper portion I0 and akconical lower portion II. The lowerend is closed by a revoluble discharge valvev I2, posif tioned in a]discharge spout structure I3.V The valve, it wilLbe'notedL is of suchconstruction as topermit the discharge of Vvmaterial from the casingbutwill" prevent. the entrance ofv air into the lowerv end of thecasing. Y

[Atthe upper end of the separator is an air exit piper I4l`which extendsdownwardly a sub-y stantial distanceinto the upper end ofthe casing.''The said 'exit pipe is arranged to be concentric withnthe. axis of theseparator and connectstwithan air discharge pipe I5. The dust ladenair,isintroducedinto the cylindrical upper portion of the 'casing through aconduit I 6 which cormniuni'pates'A with the separator casing'through a.wide nozzle lI'I offordinaryv construction so as to'im'p'art .to the'dustladen air a whirling movenient within the.separatori casing.Theflow pat# tern formed by the air within the casing consists of anouter spiral substantially as indicated This spiral moves ldownwardlyfrom the inlet toward the discharge end of the casing; The whirlingmotion of the air serves to throwl the dust particles outwardly innerspiral, the greatest diameter of which conforms to the diameter of theair exit pipe I4. This inner spiral of air is of the outer, or dustprecipitating, spiral and terminates at its apex in a stem-like columnI9.

Inasmuch as the diameter of the upper portion of the casing isrelatively large,r the dust strata formed in this portion of the casingis relatively thin. However, it increases in thickness toward the lowerend of the separator. Consequently there is a strong tendency for thedust, particularly the less dense portion of the strata, to be picked upby the inner spiral. In addition to the dust picked up by the innerspiral inthe Zone where the inner andk outer spirals meet, the whippingabout of this stem-like column within the restricted area of theseparator casing has a pronounced tendency to agitate the precipitateddust in the restricted lower end of the casing so that this dust willrbe picked up and held in suspension in the inner low pressure spiral ofair and carried out of' the casing through the exit pipe I4.

In order to overcome this -objection the present invention includes theprovision of a suction conduit which extendsdownwardly through theseparator in alignment with the axis thereof so that the dust, setinmotion at the zone where the inner and outer spirals meet and by thesaid stem-like column I9 of the low pressure inner spiral of air, willbe drawn upwardly through the said conduit 2D by the action of a fan27|, interposed in the said'conduit, and delivered into conduit I6,whereupon it is returned to the inlet end of the separator to be againprecipitated from the air.

Preferably, the conduit 20 is composed of two sections, the uppersection being fixed to the air pipe I3 by any suitable means,4 forexample, a ashing 22. 20 is designated by the reference numeral 23 andis adjustable relative to the fixed section 20. The lower end of theadjustable section 23 is provided with a suction hood 24. of greaterdiameter than the conduit and is arranged with itsV open end downwardly,hood is equal to approximately onehalf of the air exit pipe I4. The saidadjustable section is supportedby means of a rod 25 which extends out ofthe conduit 20 at the bend 26 thereof. Preferably a flashing 21 isprovided with a collar 28 through which the upper end of the rod 25extends. The said upper end of therod isfprovided with a series ofapertures 29, through which a cotter key 3l! may be inserted to supportthe rod and the hood 24 in any predetermined adjusted position. Byraising and lowering the acljustable hood section of the conduit 20itcan. be positioned in such locations that it will function, underdifferent pressures. and volumes of dust The lower end of the saidconduit U Preferably the diameter` of the lower pressure than Y beingprecipitated, to draw the dust agitated by the inner spiral of airdownwardly beneath the hood where this dust, together with the dustpicked up by the stem-like column I9, is delivered by conduit 20 intothe inlet end of the separator casing.

With the present embodiment of the invention there will be a constantdischarge of dust laden air through the central conduit 20, but it isreturned to the conduit I 6 and reintroduced with the other dust ladenair into the inlet end of the separator. The air that is dischargedthrough the air conduit I5 is substantially free of suspended dustparticles. Tests, in this regard, have shown the improvements of thepresent incention which, when applied to a cyclone separator, willrecapture approximately two-thirds of the dust which would otherwise belost,

I claim:

l. A cyclone separator comprising, in combination, a conical separatorcasing having a centrally arranged air discharge in its upper end, meansincluding an inlet conduit for introducing dust laden air into the upperportion of the casing tangentially to the inner surface thereof to forma downwardly moving dust precipitating outer spiral of air and anupwardly moving inner concentric spiral ofV air being discharged, andmeans comprising a vertically disposed interceptor conduit varrangedconcentric to the separator casing and extending upwardly through thecasing and said discharge to the exterior of the casing and provided atits lower end with an inverted hood of greater cross-sectional area thansaid conduit and positioned with its open lower end portion vin closerelation to the restricted lower end of the separator and said conduitcommunicating at its other end with the inlet end of the separator, afany interposed in said interceptor conduit whereby dust suspended insaid inner spiral of air at the lower portion ofthe separator isintercepted by said hood and directed through said interceptor conduitto the inlet conduit of the separator.

2. A cyclone separator comprising, in combinationa conical separatorcasing, a centrally arranged ai'rr discharge pipe extending into theupper end of the separator, means for introducing dust laden air intothe upper portion of the casingV tangentially to the inner surfacethereof. to form a dust precipitating outer spiral of air and a. lowpressure inner spiral for the air being discharged, a centrally disposedby-pass conduit for conducting dust particles suspended in the lowerportion of the separator to the dust inlet of the separator, the saidby-pass conduit including an upper section rigidly mounted on the upperend of the separator, a rod adjustably suspended from the upper endofthe by-pass conduit, a lower section slidably supported withinthe uppersection of said 'conduit connected to the lower end of said rod andformed with a downwardly opening hoodV of greater cross-sectional areathan the said upper section, wherebythe position of the hood may beadjusted relative to the wall of the restricted lower end of theseparator to vary the air pressures at the lower ends of the concentricspirals of air within the casing.

J OE, CRITES.

